A waistline of more than 35 inches for women and more than 40 inches for men is considered a high risk for heart disease and diabetes.

The Shape of the Nations Report, sponsored by the World Heart Federation, quizzed doctors and patients in the United States and 26 other countries to see how many were aware that abdominal fat is a big risk factor for heart disease.

Many Americans ranked that "spare tire" around the waist as being just the sixth leading cause of heart disease. In contrast, some of the doctors surveyed identified excess abdominal fat as having nearly the same impact on heart disease as high blood pressure and high cholesterol levels.

"This report confirms what we have suspected," said Dr. Stephen Daniels, a professor of pediatrics at Cincinnati Children's Hospital Medical Center, and a spokesman for the American Heart Association. "Physicians are beginning to understand that abdominal obesity is an important part of risk for heart disease, but many in the lay public are not aware of that."

Most Doctors Do Not Measure

Despite the importance of abdominal fat as a risk factor, 62 percent of the doctors surveyed said they do not measure their patients' waistlines to check for overweight and obesity. "Many doctors aren't following through by measuring waist circumference," Daniels said.

Furthermore, 58 percent of the doctors overestimated the waist circumference at which female patients are considered at risk for heart disease and diabetes, and 20 percent didn't know.

A waistline of more than 35 inches for women and more than 40 inches for men is considered a high risk for heart disease and diabetes, according to the American Heart Association. "Measuring waist circumference is a simple thing," Daniels said. "It probably should become part of the physician's routine."

Ninety-five percent of women at risk for heart disease said their doctor never measured their waist circumference. In addition, none of the women could accurately identify the waist circumference at which they are at an increased risk for heart disease and diabetes.

Seventy-one percent of women said that their doctor never told them that excess weight, including high-risk abdominal fat, boosted their risk for heart disease. Indeed, some doctors said they overlooked waist circumference in women more often than in men.

"We are living in a world that promotes obesity," Daniels said. "We have become more sedentary. We have more eating opportunities and those opportunities have higher calorie-density food. It really becomes a day-to-day approach to changing behaviors to eating and physical activity. A big step in the right direction is to build in at least 30 minutes a day of moderate physical activity."

Daniels also recommends a balanced approach to eating by "cutting down on portions, and focusing on lower-fat foods and whole grains and fruits and vegetables."

Another expert advised that the overweight see a dietitian if they need help losing weight.

"If physicians would actually measure people's abdomens, that would make it a more concrete notion for people to understand," said Samantha Heller, a senior clinical nutritionist at New York University Medical Center. "The physician should explain what the risks are, followed by a referral to a registered dietitian, so they can learn what they need to do to lose some weight," she said.

Health Crisis

Dr. David Heber, a professor of medicine and director of the UCLA Center for Human Nutrition, said he supports the World Heart Federation's report. "But I would caution that not everyone with an increased waist has metabolic syndrome," he said, referring to the combination of risk factors that are though to lead to cardiovascular disease. "We have completed studies at UCLA which indicate that there may be other genetic factors involved."

It has been estimated that 80 percent of all heart disease in the next 10 years will be linked with type 2 diabetes associated with obesity, Heber added.

"Simply taking a waist circumference, while raising awareness, does not provide physicians with the tools they need to follow up and effectively change the lifestyle of overweight and obese patients," he said. "I am convinced we need new ways to reach out to the 50 to 60 percent of the population with pre-diabetes, or as I call it, 'Diabesity.'"

Another expert thinks waist circumference is a valuable measurement that can identify people at risk for heart disease.

"Epidemic obesity is unquestionably a health crisis in the United States, and for that matter, in much of the world," said Dr. David L. Katz, associate director of the Rudd Center for Food Policy and Obesity at Yale University. "But it is a crisis in slow motion, one that has crept up on us over years, and even decades."

No one should be surprised that the public and providers alike have a long way to go on the obesity 'learning curve,' a key message from the report, Katz said.

"This is important information," he said. "The distribution of body fat is important in determining health effects. As we cultivate a more universal appreciation for the health hazards of obesity, we may expect greater attention to waist circumference as a potent predictor of cardiac risk."

More information: The American Heart Association can tell you more about obesity.